It was found that both (a) MOAB‐2 monoclonal antibodies specific for residues 1–4 of Aβ (with low affinity for APP) and (b) Aβ1–42 polyclonal antibodies specific for the amino acid sequence at Aβ40–42 specifically stain carcinoma cells (Figs 1B and 3A). Here, APP is linked to carcinoma.